Referral patterns to renal services: what has changed in the past 4 years?

Awareness of chronic kidney disease (CKD) has been prompted by the publication of several large epidemiological studies since 2002. This has led to various initiatives for the early identification and management of CKD, including the introduction of automated glomerular filtration rate (GFR) reporting and renal indicators in the primary care quality and outcomes framework (QOF) since April 2006. These initiatives were intended to promote identification of CKD and have had an impact on referral patterns to renal services. The aim of this study was to understand the nature of this impact in a catchment population of 1.2 million people.

Data were collected and recorded from all written referrals from primary care between 1 April 2004 and 31 March 2008. Referral patterns for each postcode sector were mapped using Microsoft MapPoint 2004. The effect of chance on referral patterns was modelled by using small area analysis techniques. The association between the CKD prevalence reported from QOF data and the estimated CKD prevalence was examined at post-code district level.

There were 1461 referrals in 2 years prior to the introduction of the initiatives and 2890 referrals in the 2 years post-introduction. The main reason for referral in both groups was impaired renal function or previously established renal disease. Reported comorbidity was similar between the groups. Mapping showed that there was wide heterogeneity in referral behaviour in the first 2 years of the study, which was less in the second period. Small area analysis suggested that the variation that led to the extremal quotients observed in both of the study periods was not due to random variation in referral pattern alone. There was no correlation between the reported CKD prevalence and the referral rates.

Referral patterns have changed between 1 April 2004 and 31 March 2008. The main findings were an increase in referral rate and in the age at referral without a significant change in reported comorbidity of the people referred. The main increase in referral rates was seen in more advanced CKD suggesting more targeted referral of patients with CKD to renal services.